Atrial Fibrillation Ablation

A revolutionary pioneering step in the percutaneous curative treatment of atrial fibrillation (AF) was taken by Haissaguerre in 1994. The most important point in the emergence of this treatment intervention is that a physiopathological feature of AF is well known. As is known, for a myocardial tissue to be fibrillated, it must have a critical mass. Clinically, AF does not occur unless there is a critical myocardial duct where fibrillation can occur and persist. Based on this information, Haissaguerre et al. divided the right atrium into small compartments in which AF could not continue, by drawing a line between the inferior vena cava and the superior and forming a set of lines perpendicular to this line in the right atrium. This technique consisted of the surgical Maze operations performed for years, performed with a catheter in the right atrium. However, it was important as it was the first sign that this type of procedure was also started to be performed percutaneously. The success of ablation procedures performed with linear ablation in the right atrium in the treatment of AF remained around 10%, even in selected cases. In the following years, when it was understood that the left atrium played a major role in the formation and maintenance of AF, eyes were turned to the left atrium. Again, at the end of the nineties, the same team discovered that the pulmonary veins play a very important role in the formation of AF, and turned to the treatment of AF by ablating the foci defined as focal foci within the pulmonary veins. Although the focal ablation method of pulmonary veins gave much more successful results than the linear ablation of the right atrium, revision of the technique was required due to the high risk of pulmonary vein stenosis. The next part of the story continues as new techniques, new devices, increasing success, application of the procedure in more patients.

We also started AF ablation procedures in 2005. The most popular technique at the time (still the most commonly used technique with some revisions) was to create circular ablation lines around the pulmonary veins, accompanied by three-dimensional imaging and navigation systems. Pappone and his friends were sharing their experiences on thousands of patients with this circular ablation method, which they published in the mid-2000s. In these series, success rates reaching 70-80% were reported, especially in patients with paroxysmal AF. Our practice was also based on the method of Pappone et al. First of all, patients with paroxysmal AF, with a left atrial diameter preferably less than 4.5 cm, who were not advanced age (< 65 years), were candidates for the procedure. Absence of significant concomitant structural heart disease was also among the required conditions. These patients who did not respond to drug treatment trials and were informed about the procedure were included in the AF ablation program. Left atrium and pulmonary veins opening into the left atrium were visualized by multislice computed tomography in patients who were planned for the procedure. Transesophageal echocardiography showed that there was no thrombus in the left atrium. On the day of the procedure, the patients were deeply sedated with midozolam and, if necessary, propofol. First, a diagnostic electrophysiology catheter was placed into the coronary sinus by performing femoral vein punctures. In our anatomical approach, this catheter showed us the lower border of the interatrial septum. Pigtail catheter, which was advanced to the aortic root via femoral artery puncture, allowed us to mark the aortic position. Anticoagulation was performed with high-dose unfractionated heparin, followed by SL0 or SL1 long sheath placement in the left atrium by performing inter-atrial septum puncture with the standard technique. To locate the esophagus and mark it on the 3D imaging screen, a bipolar temporary pacing catheter was inserted nasally up to the stomach and withdrawn. The time from the patient’s arrival to the laboratory until the completion of the above procedures was approximately 1.5 hours. Then, three-dimensional virtual images of the left atrium (with Ensite NavX system) were extracted using any ablation catheter. Meanwhile, the pulmonary veins were entered with an ablation catheter, and the relationship of the pulmonary veins with the left atrium was marked on the virtual display screen. The accuracy of virtual images was tested by comparing virtual images with real images obtained by multislice tomography. Then, 2 wide, circular ablation lines were created by working first around the left 2 pulmonary veins and then around the right 2 pulmonary veins, away from the mouth of the pulmonary veins. A conventional 4 mm or 8 mm ablation catheter or ablation catheter with irrigation was used at this time. Then, both circular ablation lines were combined with the linear ablation line on the ceiling of the atrium. In the vast majority of patients, another linear ablation line was created between the mitral isthmus and the left circular ablation line. However, it has emerged that this technique, which is a pure anatomical approach, needs to be modified a little more in recent years. Namely, the procedure is based on the principle of isolating the pulmonary veins from the atrium tissue. However, it is not checked whether this isolation is complete after the procedure. In parallel with the flow in the world, it has become a part of AF ablation to confirm that the pulmonary veins are disconnected from the atria by placing a spiral catheter at the pulmonary vein orifices after the procedure. In this way, the success of the transaction increases, and it is possible to see the results of the transaction immediately.

Atrial fibrillation ablation is a difficult, time-consuming, and laborious process for the patient and the team performing the procedure. For this reason, patients should be well selected and well informed about success and complications. In patient selection, it should be kept in mind that the best results will still be obtained from drug-resistant paroxysmal AF cases. The success of the procedure is low in persistent and especially perminant AF. In addition, the AF ablation technique described above is not sufficient in these patients. Additional ablation lines targeting the left and right atrium, and even complex fractional electrograms, need to be added to the technique. On the other hand, AF ablation was not an uncomplicated procedure. Even in the best centers of the world, a great complication rate of around 5% is reported. Although the rates of pulmonary vein stenosis specific to atrial fibrillation ablation, atrio-esophageal fistula, and techniques have decreased as the applied techniques have been refined, complications such as cardiac tamponade, left atrial flutter, and thromboembolic complications still remain as serious procedural risks.

The aim of atrial fibrillation ablation is to eliminate AF attacks without the need for drugs. Even if this goal is not achieved, at least reducing the frequency and severity of attacks with drugs is an important gain. However, in order to fully evaluate the response to AF ablation, it is necessary to wait 2-3 times after the procedure and make a decision. After this blind period, it is more accurate to decide whether the patient has benefited from AF ablation. The aim of AF ablation is to eliminate all symptomatic and asymptomatic AF attacks. In practice, the disappearance of symptomatic AF attacks mostly relieves us as a clinical response. However, in such a case, it should not be forgotten that the patient still needs to take oral anticoagulants according to the thromboembolic risk score (according to the CHADS2 score).

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